pexpert/arm/pe_consistent_debug.c

   1 /*
   2  * Copyright (C) 2011-2013 Apple Inc. All rights reserved.
   3  *
   4  * This document is the property of Apple Inc.
   5  * It is considered confidential and proprietary.
   6  *
   7  * This document may not be reproduced or transmitted in any form,
   8  * in whole or in part, without the express written permission of
   9  * Apple Inc.
  10  */
  11
  12 #include <pexpert/pexpert.h>
  13 #include <pexpert/arm/consistent_debug.h>
  14 #include <pexpert/device_tree.h>
  15 #include <libkern/OSAtomic.h>
  16 #include <machine/machine_routines.h>
  17
  18 static dbg_registry_t * consistent_debug_registry = NULL;
  19
  20 static dbg_record_header_t* consistent_debug_allocate_entry(void) {
  21         unsigned int i;
  22
  23         if (!consistent_debug_registry)
  24                 return NULL;
  25         for (i = 0; i < consistent_debug_registry->top_level_header.num_records; i++) {
  26                 dbg_record_header_t *record = &consistent_debug_registry->records[i];
  27                 if (OSCompareAndSwap64(kDbgIdUnusedEntry, kDbgIdReservedEntry, &record->record_id)) {
  28                         // Reserved an entry at position i.
  29                         return (dbg_record_header_t*)record;
  30                 }
  31         }
  32         return NULL;
  33 }
  34
  35 int PE_consistent_debug_inherit(void)
  36 {
  37         DTEntry         entryP;
  38         uintptr_t       *prop_data;
  39         uintptr_t       root_pointer = 0;
  40         uint32_t        size;
  41
  42         if ((DTLookupEntry(NULL, "/chosen", &entryP) == kSuccess))
  43                 if (DTGetProperty(entryP, "consistent-debug-root", (void **)&prop_data, &size) == kSuccess)
  44                         root_pointer = prop_data[0];
  45         if (root_pointer == 0)
  46                 return -1;
  47         consistent_debug_registry = (dbg_registry_t *)ml_map_high_window(root_pointer, sizeof(dbg_registry_t));
  48         return 0;
  49 }
  50
  51 int PE_consistent_debug_register(uint64_t record_id, uint64_t physaddr, uint64_t length)
  52 {
  53         dbg_record_header_t *allocated_header = consistent_debug_allocate_entry();
  54         if (allocated_header == NULL)
  55                 return -1;
  56         allocated_header->length = length;
  57         allocated_header->physaddr = physaddr;
  58         // Make sure the hdr/length are visible before the record_id.
  59         __asm__ volatile("dmb ish" : : : "memory");
  60         allocated_header->record_id = record_id;
  61         return 0;
  62 }
  63
  64 int PE_consistent_debug_enabled(void)
  65 {
  66         return (consistent_debug_registry != NULL);
  67 }
  68